Smooth Muscle Antibody (ASMA)
- Sample Type
- Standard
- Fasting
- No
- Unit
- Titer
ASMA is an autoantibody directed against the cytoskeleton of smooth muscle cells (primarily F-actin). In an Autoimmune Hepatitis Panel, it is a hallmark marker for Type 1 Autoimmune Hepatitis (AIH). High titers, especially in conjunction with elevated liver enzymes and IgG, are highly suggestive of AIH, an inflammatory liver condition where the immune system attacks hepatocytes.
Why Context Matters
ASMA can be transiently positive in low titers due to viral infections (Infectious Mononucleosis, Hepatitis C) or other autoimmune conditions like Primary Biliary Cholangitis (PBC). Titer levels do not always correlate perfectly with disease activity.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Smooth Muscle Antibody (ASMA):
Official Sources
- EASL Clinical Practice Guidelines on the management of autoimmune hepatitis - PubMedpubmed.ncbi.nlm.nih.gov
- EASL Clinical Practice Guidelines: Autoimmune hepatitis - PubMedpubmed.ncbi.nlm.nih.gov
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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